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Post by Juan on Jan 3, 2008 17:07:55 GMT
Edited due to not really being that constructive.....lol. Soz Juan ;DGood man Adam,cheers. Gotta say I'm having difficulty seeing how this will work along with the others Martin but fair play to you for thinking outside the box.If nothing else and it doesn't work then you've eliminated going down that route and it appears you're having fun pursuing this project so that seems fair enough to me. BTW,has Will had it out for its Maiden voyage yet?
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Post by adspeed on Jan 3, 2008 21:50:33 GMT
Knowledge, I have just clocked you on another popular forum for scaff-poles saying that this engine is to be 'rather revvy'......... Gotta say the combination of a 24mm carb and the back plate are really not lending themselves to be revvy. At 125/170 its never gonna be a rev monster especially with a PM copy. As I think you said a 'power reed' kind of induction was used for a period on X'ers. I'm presuming the main inlet is controlled by the crank webs as normal, so for me as this does not require the reed. I'd a chosen to use a flat reed, one with only a couple of petals such as used in some autos . Positioned at the top of a manifold to leave a good sized main standard induction. I'm not sure why you chose to use the bridge and can only imagine its restricting the whole thing. Its not an avenue I would have gone down but hey......... My route for the Polini would be standard induction 28mm carb and raise all the timings. Actually how did you raise the transfers there doesn't seem to be a packer, so have you raised them with ya porting tool???
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Post by tony on Jan 3, 2008 22:17:20 GMT
is it running martin?
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Post by Juan on Jan 4, 2008 0:07:56 GMT
I have just clocked you on another popular forum for scaff-poles I presume this is in the "chat" area that us mear mortals have no access too?I won't dis the LCGB as it's a fine forum for what it is but every referance I've ever seen to Coop's has been deleted unless it derogatory and no one has followed it up in favour of them. Adding my own thought's,I love Lambretta's(if they're fast) but I would wish the general ownership would be a little more accepting of others and less defensive.Obviously this doesn't apply to the members here or on some other boards but we all know what I'm getting at.
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Post by knowledge on Jan 4, 2008 21:10:55 GMT
I've also heard rumblings from trusted fellows in the trade that there are several design issues with it. As such I'd be dubious about copying any of it's qualities. There undoubtedly are issues with the RB, and myself and Tony have had some design issues brought to our attention. We are also aware that there are tuned and dyno'd TS1's making a good deal more power than an out the box RB22. The two points I would make are that the RB makes it's power in a very different manner to the TS1, creating a very different ride for the owner, and secondly, perhaps the place to discuss the RB is on a Lambretta forum (though everyone on the LCGB forum are treading VERY carefully around the subject of the RB - as if it would be sacreledge to say anything nasty). I'm not trying to cut this discussion short Breezer, but I come here for a bit of Vespa talk, not more bloody lambrettas. Knowledge, Gotta say the combination of a 24mm carb and the back plate are really not lending themselves to be revvy. At 125/170 its never gonna be a rev monster especially with a PM copy. Well, yes and no. Undoubtedly, the 51mm stroke will lend itself to revviness, but mainly by comparison to my previous 58mm stroke machines, but I agree that the 174degrees does not sound like a rev-monster. It is a PM pipe, it's just it's a PM pipe for a Speedfight 100, cut-n-shut into a Vespa snail (a surprisingly easy conversion, as it happens) The inlet in not controlled by the rotary valve. The casing have been opened up allow fuel to be drawn on demand. The crank is Muzzichelli, so it flows most of the incoming charge when the cut-away is presented to the inlet port, but this is no disadvantage. So yes, the reed valve is required. I'll have to sketch a picture and post it as a couple of people are having difficulty understanding that the bridge forms no obstruction to the incoming mixture. If you'd held the components in your hand, you'd understand immediately, but I now realise that people are not grasping the principle from the photos. Leave it with me..... The ports were raised the "hard" way using a proper right-angled tool. I let Will do it himself and I feel he's made a pretty good go of it. We took about 5mmoff the bottom of the barrel. We didn't want to take just 4mm off the bottom, as we wanted to start from the lowest possible exhaust timing. Yup, not a bad idea, but there are some other factors that have affected the chosen route of this tune: * Where possible, we have used the parts we already own (eg 24mm carb, a Polini barrel for £3, a lump of ali I was given etc etc) * If we start at 24mm carb and conservative porting, we can develop the engine together, which is fun. * We are aware that this barrel may not last very long (this is the last oversize) and we may need to source a new barrel some time soon. * Will is our son. He's 17 and been riding for a year. I trust him and he is a safe rider. He is also my best mate, but I would never be able to look my wife in the eye or forgive myself if I helped built him a rocket-ship and he got hurt. Therefore, developing a fast fun-scooter is more important than building a very-fast scooter. Given your recent change of domestic circumstances Adam, I guess you might be able to relate to some of that last paragraph. I hope this huge post has been helpful.
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Post by knowledge on Jan 4, 2008 21:15:21 GMT
No mate. reality bites. Will has got to do some revision for A levels exams which start next week. We got a bit delayed in the time we had on NYD when we had to swap various cables as we converted from a teleflex gear cable back to the tradional two cable system. Various components need changing or removing, inclding some electrics, so the scooter is in many pieces as I type. I don't want to do it on my own while Will revises. Where's the fun in that? Perhaps Sunday pm?
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Post by adspeed on Jan 4, 2008 21:28:05 GMT
Wow you seem to have an answer for everything pal.... So will raised the transfers....for me the angle of the dangle of the transfers is a fairly important item and would have opted for a cheap packing plate.......(Please don't comment on this.....4mm off bottom? again please don't comment) I can't be arsed anymore....Its brought a lot of enjoyment and smiles to myself and people I have shown it to......good luck......looking forward to seeing the dyno sheet.
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Post by knowledge on Jan 4, 2008 21:35:20 GMT
hmm.. didn't norrie use 30mm carbs on rotary motors back in the day Yes, but only on his most powerful race engines. LC1, for example. I'm no romantic, and I'm not a great fan of Norrie or his ego. There are times when I have enjoyed his company emensely, and other times when I have not. His tuning book is the most disappointing £8 I've spent recently, and not a patch on Webster's tuning maual that he was trying to emulate. However, I feel that his advice about carb size makes sense. There is more horsepower to come, but the carb size, manifold and reed are well suited to the anticipated performance (at this stage) I think I understand what you are saying, but believe me, the piston skirt does not obstruct the port. Yup, we might get more from one big hole and a bigger carb, but now I have detailed my reasons in my reply to Adspeed, perhaps you'll understand. Thanks for your comments, Martin
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Post by knowledge on Jan 4, 2008 22:09:00 GMT
Does this help? Note the location of the bridge, in relation to the divider on V force reed valve.
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Post by Juan on Jan 4, 2008 22:53:03 GMT
For my mind the diagram does help to show the anticipated flow although I'm still unsure on how this will work in practice but,as you said,it's all good fun.
And £8 for Norries manual?Most places I've seen knock them out for around a fiver.If memory serves I think it was just the collection of articles he did for Scootering in the early days but I could well be wrong on that.I was alway intending to scan them sometime and host it on-line,I may well do that yet.
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Post by knowledge on Jan 4, 2008 23:18:30 GMT
Just a word of warning about scanning and posting Norrie's stuff; he is very hot on copyright.
Quite rightly, I suppose.
Martin
PS £8 inc P&P, I think.
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Post by Juan on Jan 4, 2008 23:21:58 GMT
Yeah,but I never said I'd have it in a public place. Fair enough with P&P,that sounds about right.
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Post by adspeed on Jan 4, 2008 23:49:19 GMT
Is it April fools day or what.......... For me and hopefully others, we didn't need a sketch..the idea and amount of work is rediculous. All this work cos you don't want a fast engine for your son!! . For me I reckon you'll be lucky to increase power from a standard kit 8-10HP. People with loads more 'knowledge' than me have been in tears over this. Smallframe owners builders and tuners on here try discuss it with you but as always you have an answer. You will no doubt disect this post and have an answer for everything I say......I hope you will post the dyno sheet as I fail to have spotted any results for your other over documented work on any other forums!!!!! 'Wonder why they nicknamed him knowledge?'
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Post by knowledge on Jan 5, 2008 0:32:00 GMT
I am interested in the other people who have been in tears about this. I would like them to contribute to this thread, not just to you Adam. So far, I only have your word about the massed ranks of tearful critics awaiting the outcome of our approach to tuning this engine.
The dyno sheet for the PK75 we built does exist, somewhere, but Andy (Scootering editor) did mention it in dispatches from his report on JB Tuning's open day in his magazine.
What a crass statement. Of course I do. Of course I have the explanations, but they're not intended as put-downs and I don't think that they read as such. My answer are there to stimulate discussion and debate. Can you not see that? We thought about this long and hard before we built the engine so it should come as no surprise to anyone that I can justify our approach to this. I really don't know why you ask questions, then get annoyed because I have an answer.
Who else is infuriated with my answers?
Who else can't accept that we are at the start of development?
Who else is disappointed in us sharing this information?
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Post by tony on Jan 5, 2008 0:47:57 GMT
hi martin, i think its great another vespa smallie project is on the go. I do think that you'll have to redo all this inlet.. not so much for the boost idea but simply that the area drawing in from the crankcase that you've opened ,is simply far far too small to be effective. It may run but i feel it would have been much better just leaving it rotary with such a small opening. I'm not sure the motor will draw enough to lift the reeds that high. Its a good job you did only use a 24 on such a small opening, a larger carb wouldnt work well at all unless the pipe was something else and sucked incredibly well. But the auto pipes are nearly all too small in the body diameter to create the pulses required for that. But good luck.. dyno day will be interesting.
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Post by adspeed on Jan 5, 2008 8:44:29 GMT
Quick question, .....you said you took 5mm off the bottom and do not use a packing plate.
Are you using the same compression height piston if so where do the bottom of the transfers sit at BDC? 5mm below the top of the piston....? And then you raised the transfers +5mm by hand?
de·vel·op·ment
the act or process of developing; growth; progress:
If I were developing say anything really I have a goal, a target I want to acheive, say +20% torque on standard kit, beat my pals TS1, 30HP etc. etc. You have put many hours into this so...What was your primary objective and what is it to achieve....?
Ok maybe 28mm carb and big holes big timings might not be suited to ya son just yet, surely a straight Polini kit wacked on and a cheap torquey Leo doo daa or Polini would be easier to ride and suit him better??? easier to ride, no need for up and down the gears all the time, and leave the experimental/temprimental unknown characteristics of this stuff to maybe yourself. Actually forget it, it doesn't matter....I must try harder. Oh and the guys that were in tears have 'forgotten more than we will ever know' ......
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Post by knowledge on Jan 7, 2008 20:37:25 GMT
Hmmm. Moving on....
Tony, thanks for that. The first stage of the development was going really well until we tried to fit the exhaust. Unfortunately, there is a sufficient discrepency between the angle-of-the-dangle on the exhaust flange to upset the rest of the pipe. As a result, I'm going to have to cut and shut the exhaust again in order to get it to line up. This wouldn't be so bad, but it means that the pipe won't be a universal fit between the 75 and 136 engine, and I've just given it a new coat of VHT paint.
Whilst that appears to be a set-back, it will allow me to address another issue with the pipe, in that the header pipe won't allow the rear tyre to be removed and fitted while it is in situ. This wasn't such a problem on the 75cc motor, but was a major pain in the arse on the 136.
The good news is that the inlet manifold sits nicely in the hole in the frame. This was always a cause for concern as we didn't have a dummy frame to test it on prior to welding, and now we have fitted the engine, we are pleased with the result.
The down-time on the frame has given us the chance to address some rather horrible bodges put there by the origianl Italian owner, so I have welded up the original lock, in favour of the under the seat pull catch. It won't improve security greatly, but it might improve the asthetics a little (pass me the red-lead paint).
On your advice Tony, I'll start looking for some more ali tube so I can make a 26/28mm swan-neck manifold. It would seem to be the general consensus as to where we taken the development, but tracking down such a tube might take just long enough to give us time to do some testing on the engine in it's current condition.
Thanks for the warning about the pipe. We will need to bear this in mind.
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Post by knowledge on Jan 7, 2008 20:55:17 GMT
hi martin, i think its great another vespa smallie project is on the go. I do think that you'll have to redo all this inlet.. .. dyno day will be interesting. The advantage of the system that you see here is that I can go backwards if required. OK, I can't make it rotary again, but I can step-back to a Malossi reed on the three studs, or go the whole hog and cut the casings open and shove the V-force between the two halves of the crank case. As you have witnessed first-hand, my tame ali-welder is pretty good. Intersting that you mentioned the dyno, because there is going to be a very intersting article in next month's scootering about Dyno's. Sticky has been around the country testing the same bike on various dealer's dynos, and the results have been far outside the parameters of just temperature and air pressure. I chatted to JB about this last week, and then I telephoned Sticky to mention something that I had heard about the relative power outputs of the 500cc master engine, and the 400cc unit as fitted to the X8. Too late for inclusion, as Sticky had already submitted the piece for publication. People have enough trouble understanding dyno graphs as it is (I count myself amongst those people). My fear is that the casual reader may have their opinions reinforced by the article if they already think that one tuner isn't as good as another, simply because the dyno figures are different. Let's hope Sticky can clarify this in words and pictures. I look forward to reading it.
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Post by knowledge on Jan 7, 2008 21:01:28 GMT
Oh and the guys that were in tears have 'forgotten more than we will ever know' ...... Oh, you mean Harry Barlow? He is a very good tuner. I like Harry a lot. We don't agree on everything, but I still think he's a top guy, and very eloquent. The 5mm off the bottom was because of a change of compression height when changing from an early Polini piston to a late Malossi item. The transfers were raised by about 1.2mm, and re-angled to discharge across the crown of the piston (except the boost ports opposite the exhaust port). All ports line up with the crown at BDC
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Post by ozoap on Jan 7, 2008 21:10:27 GMT
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